The Venereal Disease Research Laboratory microflocculation (VDRL) test, especially the quantitative test is well standardized, simple, rapid and, at present, the most widely used non-treponernal test in serodiagnosis and follow up sturly of syphilis. However, the UDRL test result could be influenced by room ternperature, especially in summer and winter in Korea in the abscence of proper air-conditioning and heating. This study was undertaken to evaluate the effect of room temperature on the VDRL test result and to determine the critical temperatures which alter the test result. Eighty six VDRL-reactive serum samples collected at the Soonchunhyang Medical College Hospital and the V.D. Clinic of the Chung-Ku Public Health Center in Seoul during the 7 months periods from September 1982 to March 1983 were used. The results obtained were as follows: The change in the VDRL titer was not obscrved at room temperature of between 18 C and 32 C 2. The VDRL titer became weakly reactive on the same titer or lowered to half titer at room temperature of below 18C. R. The VDRL titer increased two fold at room temperature of above 32C.-countinue-